Device for controlling an electronically operated printing machine



Nov. 20, 1962 A. MAUDUIT 3,064,561

DEVICE FOR CONTROLLING AN ELECTRONICALLY OPERATED PRINTING MACHINE FiledJune 5, 1961 4 Sheets-Sheet l SELLICT/O/V conpmnron l0 1 I /20 CORESSTORE l 9 I PRl/VT CONTROL mPur/[R I2 ch11: REGISTER 13 2 can:[LL'CTROA/IC Qmmflrmg) Q TYPE Mia-L C K F/GQ/ Nov. 20, 1962 AM DEVICEFOR CONTROLL AUDUIT ING AN ELECTRONICALLY OPERATED PRINTING MACHINEFiled June 5, 1961 4 Sheets-Sheet 2 WRITING CIR U17 4 man COMPUTERCHARACTER 3 t INPUT x 3 mwonr Q, REGISTER 3 Q V l/vsmucr/onl -3;READ/I16 CIRCUIT 6 REGISTER 1 l l w gjlgg'f; our/=07 A'z'a/srm-8 Amiga-LINSTRUC7'I0/l I k A/VAL)$R'5Z PAR/7) u z cflfcll' I LIA/E SPACECOMPARATOR/,0 CONTROL I l v 120 conzs STORE ll PRINT CONTROL AMPLIFIER[2 J L, L 2; w #1 con: /20 TRANSDUQEAS fie'a/srmr kn 1 A I T I i F/ G 2Bi: STE/KING DEV/CE I y can: MR/1Z0 rm: M15121 2 '1 Nov. 20, 1962 DEVICEFOR CONTROLLING AN ELECTRONICALLY Filed June 5, 1961 A MAUDUIT OPERATEDPRINTING MACHINE 4 SheetsSheet 3 I PULSES l 6 I FIG. 2 F16. .3 I I m,FIG. 4 con/r004 i C/RCl/IT 30 I i II Iu I 20 Z5 1 I CHECK Bl ICOMPARATOR g I 27 -v an: E C/RCU/T II ""124 I I20 (0/?[5 STORE 24 4 I x0am C00 cwcu/r $5 22 2/ m'cmw/c I LOCK i /4 Fl G 3 I r W41: m 777W Nov20, 1962 A. MAUDUI DEVICE FOR CONTROLLING ANTELECTRONICALLY 3064561OPERATED PRINTING MACHINE Filed June 5, 1961 4 Sheets-Sheet 4 [I 2SELECTION OF CHARACTER m 2 .STR/lf/NG co/vmol. or cAAAAcTER m t 2SELECT/0N or CAARAcTER m I .sTR/AAva CONTROL OF cHARAcTER m I L 3 sureT/ON or cAARAcTER m +2 RESPONSE OF TRANSDUCERS 0F Cl/HRHCTER mSTR/h'l/VG CONTROL OF CHARACTER m +3 sewer/01v OF CHARACTER m +4 ANDCHECKING 0F CHARACTER m RESPONSE OF TRANSDUCERS 0F CIMRACTER 074-] FIG 06 9mm:

iinite t'ates atent ice v 3,654,561 DE VICE FOR CQNTRGLLING ANELECTRGNI- {JALLY OPERATED' PRINTING MACHWE Andre Maudnit, ConfiansSainte Honorine, France, assignor to Compagnie ties Machines lBnll(Societe Anonyrne), Paris, France Filed June 5, 1961, Ser. No. 114,95Claims priority, application France June 14, 1960 11 Claims. (Cl.1tl193) The present invention concerns a device for controlling an.e;ect ronically operated printing. machine, by means of which it ispossible to check the identity between the printed text and the textsent to, the control circuits of the printing machine in coded form. Theprinting machine for which the. device is intended s a fullyelectronically controlled machine which receives its information from anelectronic computer or any complex data-processing assembly. The.information takes the form of coded characters, each character beingrepresented by a succession of binary pulses. The items of informationreceived also comprise working instructions, indicating more especiallythe spacing between two lines, called the jump of the paper.

The printing device comprises a type drum formed of an assembly ofidentical wheels. If the printing line comprises 120 characters, 120wheels each bear all the printing characters or types distributed ontheir circumference, or 60 wheels each bear tWo series of types,depending upon the constructions. The Wheels rotate with an absolutelysynchronous movement, so that they can all print the same character atthe same instant in the cycle. The printing proper is carried out by 120striker hammers which apply the paper againstthe type, thesethammersbeing actuated by control electromagnets. The inking is effected by aninterposed ribbon or carbon paper.

The principle of the-electronic printing control is as follows: The typedrum drives in its rotation a codegenerating drum adapted to generate inan appropriate pick-up member a number of characters coded in accordancewith the internal code of the computer equal to the number of charactertypes on the printing drum. The said generator may consist of'anassembly of toothed wheels, the number of which is equal to the numberof binary positionsof a. character. The pick-up member then consists ofthe same number of magnetic heads bearing two windings, one of which isthe primary Winding and the other a secondary winding, so that thetravel of a tooth past the air gap of the magnetic circuitvaries thereluctance of the latter. A binary l or corresponds to the presence orabsenceof a tooth on the wheel. The generator may also be a drum bearingmagnetic marks and the pick-up member mayconsist of magnetic readingheads. The arrangement of the teeth or marks on the periphery of thedrum is such that the coded character is generated in the pick-up memberslightly before the corresponding printing: character takes up aposition in front of the striker hammers. Appropriate amplifiers areconnected to the windings of the pick-up:

member.

Before theprinting of a line, all .the characters of I one line havebeen registered in coded form in a store having 120 addresses.

Thecharacter produced by thecode generator is written in a registerandsuccessively compared with each.

character extracted one-by-one from the preceding store. If ,thetwocoded combinations compared are identical, a signal is emitted by the.comparing device and energises a position of an intermediate registercomprising 120 positions. When the'lZO characters ofthe line have beencompared with the code character, a number of positions of theintermediate register may thus have been energised and then transmit apulse to the striker hammers, so that the character is printed in eachof the corresponding line positions.

The cycle continues. Each character of the code-generating drum is thuscomparedwith the characters of the line, so that the whole line has beenprinted at the end of the cycle.

The succeeding line is thereafter entered in the addressable store, andthe printing thereof is carried out in ac cordance with the sameprocess.

The checking devices already known for this type of printing machineonly partially check the operations. They are intended to check that thecoded characters transmitted through the device do not unndergo anymodifications in the course of the various transfers, and that aprinting order has been transmitted to the striking control device forall the characters of the line before the change-over to the succeedingline. They do not permit of checking that the striking has beenefiective and that the struck character does in fact correspond to thecoded character registered in the store in the corre'-- spondingposition.

In contradistinction thereto, it is possible by means of the deviceaccording to the invention to effect a complete checking of the printingoperation. It must be understood by this that it takes effect only fromthe instant when the mechanical striking device has become operative, inorder to print the. character on the paper, and that it checks that thestriking is accurate, that is to say, that when the character has beenstruck, the position of the printing wheels is such that the codegenerated by the code generator does in fact correspond to the characterregistered in coded form in the store.

This result is obtained by the checking device according to theinvention, which comprises a transducer device emitting a pulse eachtime a striking device has been actuated, a comparing device whichcompares the coded character transmitted by the processing machine'witha character coded in accordance Withthe'same conventions, generated by acode generator fast with the printing'de vice and generating a comparingcode in the case of identical characters, so that each emission of acomparing code which does not coincide with the emission of a pulseemanating from the transducer device, or conversely any pulse of thetransducer device not coinciding with a comparing pulse produces theemission of an error signal.

For a better understanding of the invention and to show how it may becarried into efiect, the'same will now be described, by way of example,with reference to the ac-' companying drawings, in which:

FIGURE 1 is a general diagram illustrating'theprinciple of an electronicprinting machine,

FIGURES-2 and 3 are a general diagram of the'electronic circuitsassociated with the printing devices,

FIGURE 4 is a plan view of FIGURES- 2; and 3 in combination,

FIGURE 5 indicates the constitution of a printingtcycle,

and

FIGURE 6 indicates the distribution of the various printing and checkingoperationsin the course of five successive cycles.

In FIGUREl, there are shown:

at 1 the printing typedrum,

at 2 the code generator,

at 3 the character store,

at 4 the store selecting circuits,

at 5 the store writing circuits,

at 6 the store reading circuits,

at 7 the input register for the characters,

at 8 the output register of the store whose-capacity is 1 character,

at 9 the register in which is written the character ema- 3 nating fromthe code generators,-having the same capacity as that previouslymentioned,

at 10 the comparing device in which are compared the characters comingfrom the registers 8 and 9,

at 11 the register having 120 positions consisting of 120 storageelements brought to the state 1 each time quality is detected in thecomparing device 10,

at 12 the 120 energising devices for the striking control hammers,

at 13 the striking device, and

at 14 an electronic clock controlled by a toothed wheel rotatingtogether with the drum.

The connecting channel 15 combines the printing circuits with theelectronic computer. The characters are sent in coded form. Theconnection may be in series or in parallel for each character, withoutinfluencing the operation of the printing machine. The characters of onelineare sent in series.

The principle of the operation of the printing machine may therefore befollowed from FIGURE 1. All the characters of a line are unitarily sentto the register 7, in which they are passed through the writing circuitsof the store 3. The first character is written at the address 1, thesecond character at the address 2, etc., the selection being effected bythe circuits 4, in which the store address is advanced by one unit ateach writing of a character. When the entire store is full, the rotationof the printing drum 1 is such that the first coded character isgenerated by the code generator 2 and is written in the coded characterregister 9. A further selection from the store 3 is effected from thefirst character, which is extracted by the reading circuits 6 andwritten in the register 8. The characters written at 8 and 9 arecompared in the comparing device 10. If they are identical, an outputsignal is emitted, which writes a binary 1 in the first position of theregister 11. The character is re-written in the store. The selectionthen continues, and the 2nd, 3rd 120th characters are progressivelyextracted from the store, sent to 8, compared at 10 with the same codedcharacter, and each time that identity is detected the correspondingposition of 11 is registered. When the 120 characters have thus beentested, a number of positions of the register 11 have been brought tothe state 1. In the same time, the first type of the printing wheels,slightly retarded in relation to the coded character of the codegenerator, is positioned opposite to the striking hammers. A strikingorder is given from the synchronous clock rotating in step 'with thedrum 14, so that the content of the register 11 is applied in the formof electric pulses to striking control devices 12 which actuate theelectromagnets of the device 13 acting on the striking hammers, only inthe positions in which the first character must be struck. The secondcharacter is then generated by the code generator and is written at 9.The store 3 is again entirely read, each character being compared withthe character written at 9. The process continues until all the printingcharacters have been compared with the characters of the line and theentire line has been printed.

The operation thus described is synchronised by the rotation of theprinting drum. Considering a machine printing N lines per second, theprinting duration of a line is at most seconds. This time T will becalled the major cycle of the printing machine. If the drum comprises nprinting types, the time t reserved for the comparison of a characterwith the characters of the store and its printing is at most equal to twill be called the minor printing cycle of the printing machine. Infact, I is smaller than this value, because if the drum has a continuousrotational cycle the types 2: are not distributed over the entireperiphery of the printing wheels. They are distributed along an angle onin accordance with FIGURE 5. The angle 6 is a dead angle used betweenthe comparing and printing cycles of two successive lines for the jumpof the paper and the filling of the store 3 with all the characters of aline.

In a machine constructed in accordance with these principles, operatingat 300 r.p.m. and possessing 60 characters per type wheel, T=0.20'second and t is lower than In fact, the 60 types are distributed alongtwo-thirds of the circumference (u=240) and consequently the duration ofa minor cycle I is 2.2 m./s. V

The principles of the operation of a printing machine thus having beenset forth, there will be described in the following the devicesaccording to the invention and the application of the checking means forensuring accuracy of printing. In this description, reference will bemade to FIGURES 2 and 3, in which the parts illustrated in FIG- URE lare again to be seen.

In addition thereto, there are shown the members listed in the thefollowing:

at 20 a checking and comparing device of similar construction to thecomparing device 10,

at 21 a coded character register similar to the register 9,

at 22 a delay circuit disposed between the coded character registers 9and 21,

at 23 a set of 120 transducers associated with the striking devices,

at 24 a register composed of 120 storage positions, connected to thetransducers 23,

at 25 an intermediate register having 1 position registering thecontents of one of the storage positions of 24,

at 26 a parity key checking device,

at 27 a gate circuit,

at 28 a circuit for modifying the 7th and 8th positions of thecharacters,

at 29 a circuit for scanning the 8th position of the characters.

There are also shown in FIGURES 2 and 3, at 30 the general controlcircuits of the printing device, at 31 the instruction register, at 32the instruction scanner, and at 33 the paper jump control circuits.

In order that the operation of this assembly may be understood, it willbe assumed that the printing machine, which is initially in theinoperative position, is connected to an electronic computer. Itreceives from the latter a working instruction signifying that all ofthe characters of one line will be sent to it from the store of thecomputer; a succession of instructions will thus be sent, positioned at31 and scanned at 32. They comprise a certain number of indications, ofwhich the coded indications of the spacing between the line beingprinted and the line i which will be printed under the control of thepresent instruction, this information bearing the name jump control andbeing registered at 33.

The instant of the cycle at which the printing machine receives theinstruction relating to the printing of a line will hereinafter bedefined.

The process of printing a line, which lasts a major cycle T, may bedivided into 3 successive operations:

(1) Registration of characters in the store 3.

(2) Comparison and printing of the characters typeby-type. Y

(3) Printing check.

If, in accordance with the preceding example, there are character types,the duration of the second operation is 60 minor cycles 2, and theduration of the third operation is of the same length, but itsperformance is staggered by several minor cycles in relation to thesecond operation.

(1) Writing of the characters in the store-When a line has to beprinted, the characters are successively sent into the input register 7,character-by-character. These characters are coded in accordance with abinary combination called the internal code of the computer and comprisea number of binary digits, for example 6, which are introduced into theregister 7, in series or in parallel depending upon the internalarrangement of the computer. In the electronic circuits of the printingmachine, on the other hand, the binary digits constituting thecharacters will preferably be carried in parallel betwen the variouswriting and storage circuits. A 7th binary digit accomparties thecharacter, which is the parity key of the character. It is. a 1 if thenumber of 1s contained in the character is even, and a if it is odd.

Each time a character is introduced into 7, a control pulse is sent from30 into the selection circuit 4 of the store 3, which comprises aswitching circuit, so as to select successive store lines, the store 3consisting of a matrix of magnetic cores having 120 columns, selected inaccordance with the principles of double coincidence which is Well knownin this technique. The character written in 7 is transferred into thewriting circuits after passing through the register 8 and after thechecking of the parity key 26. This check has another object which willhereinafter be explained.

Each line of cores of the store 3 comprises, not 7, but 8 cores. Thecharacters are written in 6 cores, while the seventh contains the paritykey. The eighth is left in the state 0 in the initial writing of thecharacters. This core is dependent upon the device for the checking ofthe printing as hereinafter described. It will be changed over to thestate 1 after printing and checking of the character. The 120 charactersare registered in the store 3.

(2) Printing of the line.When the store is completely filled, theprinting process starts. It is carried out in accordance with thegeneral principle hereinbefore describedv by comparison, in thecom-paring device 10, between the coded character emanating from thecode generator 2 and all the characters extracted unitarily from thestore.

Each character is read in the reading circuits 6 and then sent into theregister 8. In fact, it is not 6 binary digits, but 8, which areextracted from the store, only the 6 binary digits of the characterbeing transmitted to the comparing device 10, plus the parity code ifitis generated by the code generator at the same time as the character. Ifthere is not identity, the comparing device 10, transmits no signal. Ifthere is identity, a signal is sent to the register 11, which is al-position register consisting, for example, of 120 magnetic cores. Onthe core corresponding to the position of the character in the printingline is capable of changing its state under the action of this control,because the switching device which conditions the selection ofcharacters at 4 also acts on a device for the successive selection ofthe cores 11, so that a current is sent only to the selected core.Therefore, at the end of a complete reading of the store 3, only acertain number of cores are in the state 1, these cores corresponding tothe positions of the characters which, since they are identical to thecharacters generated by the code generator, must be printed. When allthe store has been read, an electrical signal calledthe reading currentis sent into the set of cores of'11, and the output wires of the coresare passed through an amplifying system 12 having 120 independentcircuitswhich, under the action of the variation of the current.

With re-.

must obviously be absolutely synchronised with the rotational'movement'of the printing drum. The electronic clock 14- performs thissynchronising function. It comprises a toothed wheel having 9 teeth androtating at a speed 10 times higher than the speed of the drum. Theseteeth travel past a magnetic head similar to that provided for'usewiththe code generator. The signals re'-. ceived, in suitably amplifiedform, are recurrent signals whose period fixed the duration of a minorsignal as previously defined. They are employedto. fix the commencementof the reading of the cores of the register 1-1- and hence the controlof the striking devices. They are sent to the general controlcircuitsand serve as a. time base for determining the succession, which willhereinafterbe more clearly defined;

(3) Printing check.In order that the printing may be correct, it isnecessary that:

(a) the character should not have changed in the course of thesuccessive transfers,

(b) the striking order transmitted by. the amplifying system shouldeffectively result in a mechanical displacement of the striking hammer,which has the effect of'applying the paper to the character on the typewheel, and

(c) the printed'character should agree with the character expresed incoded form.

The check (a) is made by checking of the parity key before the writingin the store 3' and after each extraction from the store.

In. order to effect the check ([7), a printing device such asthatdescribed in the aforesaid patent application is employed: The.displacement of the striking hammer varies the air gap of an auxiliaryelectromagnet which carries a receiving coil on its magnetic circuitThis member will be called the checking transducer-toindicate that amechanical displacement has been used to create an electrical signal.

The signal given by the coil will be employed to effect the check (0).

The transducers 23 are combined with a set of 120 magnetic cores (24)constituting a register. If in the course of a minor cycle 1 a number ofcharacters have been printed, the same number of transducerswhosepositions are those of the. characters struck along the linegenerate checking signals a period of time1- after the control of thestriking of the character and change the state of 'the same number ofcores ofv the register 24, occupying corresponding positions.

During this time T, which may cover a number of minor cycles, the codedcharacter, which corresponds to the printing type which has justbeenstruck and whichhas, been registered at 9, is applied to a delay circuit22, which delays it by the duration 1', and sends it after this periodof time into thedelayed code character register 21. At the selectionofthe store 3 which follows the writing of the,.code.character in-21, thecharacters extracted from 3, and written in 8 are sent, not, only intothe.

comparing device10, butalsoin-to a comparing device 20 which-receives,on the one hand, the-said characters and on. the other hand the retardedcode character emanating from 21. In the same time, theswitching system.which: simultaneously controls the selection of the store 3-and theentry in the register; 11, controls. If

the reading of the magnetic cores of the store 24-. a core has changedits state, a binaryl is Written in the intermediate register at 1,position 25.

If'character identity is found in 20; itis because. the character ofthis. position ofthe line was. identical to thecoded; character read;attheprevious time 7'. Therefore, the printing must have been-eifected,the transducer has emitted a signal stored inthisposition of 24, and abinary 1 must be entered in 25.

A gate circuit 27 is connected on the'one hand to the output of. thecomparing-device-ZO and on the other hand to the register. 25. I

Various cases may arise:

The comparing device does not detect any identity, but the register 25is in the state No character has been printed in this position of theline.

The comparing device indicates an identity (output signal at the outputof the comparing device) and the register 24 is in the state 1. Printinghas taken place at this position of the line, which is correct since thecharacter in this position is identical to that generated at thisinstant by the code comparing device. The output of the gate 27 emits asignal.

The comparing device indicates an identity, but there is no 1 in theregister 24, or conversely there is no identity, but there is a "-1 inthe register 25: the printing is defective either because it has nottaken place or because it has taken place wrongly.

The gate therefore has two outputs, the first of which (given by an ANDcircuit) gives a 1 only if the striking has taken place and it iscorrect, while the second (given by an exclusive OR circuit) indicatesthe case of an error in appropriate visual indicating systems. The firstoutput controls the re-writing of the character in the store 3. Thecharacter is sent to the modifying circuit 28 situated between theregister 8 and the writing circuits 5.

If this output indicates an 0 or the absence of a signal, the characteris reproduced without change and rewritten in 3. The selection of thecharacter entered in the following column of the store takes placeonlyafter this re writing. If this output indicates a 1, the last twopositions are modified, because a binary "1 is entered in the eighthposition, which has hitherto been at zero. Consequently, the parity keyis reversed, and the seventh position is therefore also modified. Theregistration of the eighth position therefore indicates that thecharacter of this column is printed, that the printing has been checkedand that it is satisfactory.

The succession of the various operations hereinbefore described will bemore readily understood with reference to the diagram of the times ofFIGURE 6. It has been assumed by way of numerical example that the minorcycle t==2200 s. and that 1:5000 as. by reason of the inertia of themechanical parts. In this figure, five suc- 'cessive minor cycles t t tt and t are considered and it is assumed that at the cycle t thecharacter generated by the code generator and entered in 9 is the mthcharacter of the type wheel.

Therefore, the printing position of the character m is selected. It willalso be assumed that the beginning of the cycle is given by the signalemanating from the clock 14, which determines the control of the device12 actuating the striker hammers and that the coded character followingthe struck character is generated by the code generator several tenthsof a microsecond after the striking control.

The cycle 1 therefore commences by the control of the striking of thecharacter m in all the desired positions, and continues by thegeneration of the coded character m+l, and the selection of thischaracter, a complete reading of the store 3 lasting about 600 as. Thestriking control has determined a slower mechanical action and theresponse of the transducers corresponding to the character m willtherefore be received at the cycle t At the cycle i the striking controlof the character m+1 is carried out, and then the selection of the character m-+2. I

At the cycle t the striking control of the character m+2 is followed bythe selection of the character m+3, but in the course of this cycle, atime greater than 5000 ,uS. has-elapsed since the striking control of m(at the cycle t Therefore, a response is obtained at the cores of 24 inthe course of the cycle.

In the succeeding cycle i there take place:

the striking control of the character m+3,

the selection of the character m+4,

the control of the printing of the character m, in accordance with thecomparing process described, the two operations, i.e. the selection ofthe character m+4 and the checking of the character m, beingsimultaneous (obviously there will never be equality in the comparingdevices 10 and 20).

The'response of the transducers of the character m-l-l' will thereafterbe received in the same cycle.

Since the register 24 consists of store elements comprising cores,writing and reading cycles can never take place in the same fraction ofa cycle. Now, the response time of the transducers depends upon theinertia of a mechanical device and can consequently undergo uncontrolledvariations which might interfere with the succession of the cycles ashereinbefore described. In order to avoid such defects in operation, asimple arrangement may be provided which consists in providing twoidentical registers 24 and 24' each consisting of cores, the writingwindings of two cores of like position being connected in parallel tothe corresponding transducer. A simple switching system alternates thefunctions of the two registers, so that in a cycle, if 24 receives thepulses from the transducers, it is 24' which is readposition-by-position for checking in 20. On the other hand, in thesucceeding cycle, the writing effected in 24 in the preceding cycle isread, and the responses of the transducers are written in 24'. Thus, thewriting time may overlap the reading time, and it will be noted that thereading, which is an integral part of the store selection operations, isalways situated in the same fraction of a cycle, and that it is thewriting, related to the response of the transducers, which may undergosome shift within a cycle.

The checking device hereinbefore described therefore has the effect oflocating a 1 in the 8th core position of a line of the store 3 when thecharacter entered in this line has been printed and the accuracy of theprinting has been checked. Consequently, when a complete line has beenprinted, the 120 cores of the 8th column contains afl in the location ofthe initial "0. It is therefore possible to pass to the operationspreceding the printing of the following line, namely paper jump andfilling of the store 3 with the characters of the following line.

The scanning circuit 29 scans the state of the 8th position in order todetermine the instant when the 120 positions of the store are in thestate 1. A first arrangement will consist in carrying out an additionalstore reading when the 60 characters of the printing wheel have beencompared with the characters of the line, that is to say, at thebeginning of the cycle 5 (FIGURE 5). At this stage, it is necessary tohave identified the 120 characters with one of the 60 characters of thewheel. More exactly, this final check reading should take place 4 minorcycles after the striking control of the last character of the wheel, byreason of the response time of the transducers.

As already stated, during the time ,6, the jump of the paper inaccordance with the number of interlines indicated in the instructionsent by the computer takes place. This time is sometimes too short whenthe jump exceeds the number of several interlines, or when it isnecessary to change sheets of a certain length. Now, the printing drumcontinuously rotates and if the jump is not completed in the timeallotted thereto, a major printing cycle is lost.

In order to increase the probability of effecting the jump withoutlosing cycles T, the most probable distribution of the alphanumericalcharacters in the commonest commercial documents has been studied. Thus,the distribution of letters on the printing wheel does not follow thealphabetical order, but depends upon their frequency in the wording ofthe forms and other documents. It may thus be assumed that in a largenumber of cases the printing of a line will be completed well before the60 characters of the type wheels have been explored, and the jumpcontrol operations may be started before the end of the cycle a.

In order to benefit by this advantage, the 8th position of eachcharacter is introduced into the scanning circuit 29 at each reading ofthe store 3. This circuit is therefore disposed after the readingcircuits 6. It consists of a flip-flop having two stable states which isplaced in the state 1 at the beginning of each reading cycle. It remainsin this state as long as the sign-a1 received (8th position of eachcharacter) corresponds itself to a 1. It is returned to the state at thefirst zero signal received and remains in this state. In other words,the extraction of the first unprinted, character from the store 3 resetsthe scanning circuit 29 to Zero. If, on the other hand, all thecharacters have been printed and checked, the 120 successive charactershave a l in the 8th position, and the flip flop is not returned to zero.At the end of the cycle it sends a Signal to the control circuits, whichhas two efiects:

the control circuits send a signal to the computer, which determines thedespatch of the 120 characters of the succeeding line,

the control circuits send a signal to the jump control circuit 33, inwhich the length of the jump is Written, that is to say, the number ofinterlines between two successive printing lines. The signal starts theclutch engagement system which controls the movement of the paper, thedescription of which is of no interest to the present invention. At eachdisplacement corresponding to a line, a pulse is sent to the circuit 33,in which it subtracts one unit from the number entered until this numberis zero. The jump device is then rendered inoperative.

At the same time, the characters constituting the following line arewritten in the store 3 in accordance with the process already described.At the moment when the jump is completed and when the store 3 iscompletely filled, the printing can commence when the first character ofthe code generator is generated, and if at this instant the jump has notbeen completed, it is necessary to wait for one cycle T until the firstcode character is regenerated,

It will be noted that the instruction emanating from the computer andconcerning a line I is sent to the circuits of the printing machine whenall the characters of the preceding line 1-1 have been sent into thestore, and before it is printed. Thus, the instruction is written in 32.When the printing of the line ll has been completed, the printingmachine is thus in possession of the particulars which it requires forpreparing for the printing of the line I, in particular the length ofthe jump between the lines l --l and l.

A last arrangement also concerns the making-up of a page. The printinglines contain a number of spaces which cause characters all equal tozero to be sent into the store. These characters do not correspond toany of the characters generated by the code generator. They arelocatedin the following manner: When the characters are transferred 'from theinput register 7 to the writing circuits of the store 3, they are firstsent into the register 8 and tested in the. comparing device 20, ofwhich the second comparing element is Set at Zero. If identity isdetected, everything happens as if character identity existed in thismember. The modifying circuit becomes operative to locate a l in the 8thcharacter position, and the character is thereafter sent from 8. to thecircuits 5.

In the printing circuits, the presence of the ls in the 8th positions ofthese characters will enable them to be considered in the same Way asthe characters actually printed.

However, it will be noted that in order that this process may result inan accurate printing it is necessary to avoid confusion of the spaceswith the zeros which have to be printed within a numerical datum, andthat consequently the true zeroes will have to comprise in their writtenform a symbol by which they can be recognised. This difierentiation maybe effected wither It) in the circuits of the computer or in thecircuits accompanying the printing machine.

The various members employed in the electronic control and checkingcircuits of the printing machine may be designed with technologicalstructures similar to those provided in the electronic computer withwhich the printing machine is associated. Some particulars will be givenby way of example, but any other construction by which the describedoperations can be carried out may be adopted.

The control circuits 3t) consist of a series of logical circuits whichsuccessively supply control pulses to the circuits which they control.They consist of a succession of flip-flops connected one behind theother by logical AND and OR circuits in which the set of signals permitting the control of the action initiated by the flip-flop followingthem are combined. The actions thus controlled include: The sending tothe computer of demand signals for providing for the despatch of theinstructions and characters to the transfer channels; the controloftransfers between the various registers described, the ini tiation ofthe selecting operations. The additional time conditions depending uponthe printing cycle produce pulses emitted by the electronic clock 14'and applied to the logical circuits. The AND and OR circuits are diodecircuits of standard type which emit a pulse at the output if a pulse isapplied at each input. The other time conditions having a cycliccharacter within a minor cycle are defined by elemental rhythmic pulsesof a periodicity of 10 microseconds consisting of 10 recurrent rhythmsstaggered by 1 microsecond, in relation to one another, and called 6 6 09 The rhythmic pulses are distributed by a pulse generator which may bein the computer or associated with'the printing machine. Thus, theselection of the store 3 is initiated by the pulses emanating from theclock 14, and the address switching in a total reading of the charactercomparing cycle is automatically governed by the rhythms 6V and. 9 andthus lasts 600 microseconds.

The character registers (7, 8, 9, 21) are of the parallel type andcomprise a number of bistable circuits equal-- prising valves ortransistors or of transistor amplifiers which, under the action of apositive input pulse, change from an initial output level 0 to a finallevel 1, and in which a feedback from the output to the input maintainsthe final level 1, as long as a return to zero in the form of a negativepulse does not cancelthe efiect of the,

feedback. The transfer from one register to another is effected byconnecting together two circuits of like order through anfAND circuit,to which there is applied the transfer control pulse sent in parallel tothe 6 (or 8) circuits of the register.

The store 3 is, as stated, formed of a plane matrix comprising magneticcores having a rectangular hysteresis loop and having 2 stable states,forming a network of 8 lines and columns. Each core has 5 wires passingtherethrough: a biasing wire common to all thecores,

throughwhich therepasses a current equal to one-third of the change-overcurrent, a reading selection wire through which there passes a currentof the same direction as the precedingcurrent and equal totwo-thirds ofthe change-over current, a writing selection wire through which therepasses ,a current .equal to and of opposite di-,

rection to the preceding current, a writing wire, and a reading wire.

The selection Wires extend through all the coresof one column, and thewriting and reading wire through all the cores of one line.

current is sent. The reading selection, orrtheotherhand,

To Write a one, there isI sent through the writing wire a currentequaltothe selec tion current and of like direction. To write an 0,;- no

changes over the core from 1 to if it is in the state 1 and thereforegenerates an induced current in the reading wire, the core remaining inits state if it is in the state 0. The selection circuits comprisecurrent generators generating currents in one direction for writing andin the other direction for reading. They are combined with the wiresthrough the cores by alternately changed over switches which may betransistor circuits rendered conductive at the instant of the selection.Since reading destroys the information, successive reading and writingare carried out within an elemental cycle between two selections. Thewritten datum is either the character of a new printing line emanatingfrom the input circuits or the character which has undergone thecomparing and checking cycle.

The writing circuit 5 comprises an electronic current generator whichsends a current into the writing wire if the binary datum to be writtenis a 1; The current generator'is therefore connected to the writing wireof the lines of cores by a transistor switching circuit which isconductive for a binary 1 and non-conductive for the writing of a binaryO. The circuit 5 comprises 8 generators and 8 switching circuits. Thereading circuit 6 is connected to the reading wires of the lines ofcores and comprises 8 electronic amplifiers designed to shape andamplify the pulses collected at the reading wires during a change ofstate in a reading selection cycle. These amplifying circuits arerendered non-conductive outside the reading time in order that parasiticpulses may not be picked up. The output of the 8 amplifiers is connectedto the 8 positions of the register 8.

The comparing circuits are logical circuits which combine in parallelthe corresponding outputs of the registers containing the data to becompared, that is to say, they contain 6 circuits carrying out thebinary operation a.b+fi, and supply a signal if these six circuits givea response equal to 1, which indicates identity of the characters. Thesecircuits are constructed with the desired number of diode circuits andinverting circuits.

The writing circuit l1 consists of a set of 120 magnetic cores oftoroidal form, around which there are disposed three windings: the firstWinding is a writing Winding connected to a current generator through aswitching circuit. The switching circuit, which comprises a normallynonconductive transistor, is rendered conductive by a double logicalcondition: identity of character (signal supplied by the comparingdevice 10), and selection of the corresponding line position, whichresults in two signals being applied to an AND circuit. If theseconditions are satisfied, the current is sent into the Writing windingand changes over the state of the core. The second winding is a readingwinding connected to one of the amplifying circuits of 12, and the thirda reading control winding common to all the cores and connected to areading control current generator through a switching circuit renderedconductive by a control signal due to the electronic clock 14, so thatall the cores are read at the same time. The amplifying circuits 12 maybe transistor circuits whose power is defined by the coil circuits ofthe striking control electromagnets.

The circuits for Writing the response of the transducers 24 and 24 alsoconsist of 120 magnetic cores having a number of windings, but it is thewriting control which is this time efiected by a common Wire alternatelyat 24. and 24, while the reading is selectively efiected in dependenceupon the selection of the store 3. There is therefore a writing controlwinding connected to a current generator, so as to write in one instanceon all the cores at 24 and in the other instance on all the cores at24', each Winding of 24 being connected to a transducer in parallel withthe winding of the corresponding core of 24', a reading selectionwinding connected to a current generator through a switching circuit,and a reading winding in which a current is induced in the event of thechange over of the core underthe action of the reading selectioncurrent.

The device also comprises the delay circuit 22, which may consist of 8shift registers, each of which is intended to delay a binary characterdigit, and whose outputs are sent to the register 21.

Any other storage and Writing arrangements which may be employed insteadof the described circuits fall within the scope of the presentinvention.

I claim:

1. In a printing machine connected to a data-processing machine andincluding a plurality of striking devices and a rotating type drum, adevice for checking printing in tended to verify that the printedcharacters are equivalent to the coded characters transmitted by theprocessing machine, comprising generator means for generating a checkingpulse each time a striking device has been actuated, a character-codegenerator fast with said type drum, an equality comparing devicecomparing at each instant the coded characters transmitted bytheprocessing machine with the character coded in the same codegenerated by the said code generator, switching means associated withsaid generator means and with said comparing device, so that it deliversan error signal when identity of the said coded characters is detectedby said comparing device Whereas no pulse is supplied by the saidgenerator means, or when a pulse is supplied by the said pulsegenerating means whereas the comparing device 'does not detect identityof the said coded characters.

2. In a printing machine connected to a data-processing machine andincluding a plurality of striking devices and a rotating type drum, adevice for checking printing intended to verify that the printedcharacters are equivalent to the coded characters transmitted by theprocessing machine, comprising generator means for generating a checkingpulse each time a striking device has been actuated, a code generatorfast with said type drum, an equality comparing device comparing at eachinstant the coded characters transmitted by the processing machine withthe character-coded in the same code generated by the said codegenerator and generating a comparing pulse whenthe said characters areidentical, a coincidence circuit connected to said generator means andto said comparing device in order to be actuated at its inputs by thechecking and comparing pulses and supplying an error signal at itsoutput when only a single pulse is active at its inputs.

3. In a printing machine connected to a data-processing machine andincluding a plurality of striking devices and a rotating type-wheel, inwhich all the characters of one hne transmitted in coded form from theprocessing machine are written to be stored in a character store, anarrangement for cehcking printing and designed to verify that theprinted characters are equivalent to the coded characters stored in saidstore, comprising for each printmg position a transducer device emittinga checking pulse each time an associated striking device has beenactuated, a code generator fast with said typewheel, an equalitycomparing device comparing the coded characters extracted from theposition of said store with the character coded in the same codegenerated by said code generator and emitting a comparing pulse when thesaid characters are identical, a coincidence circuit operativelyconnected to said transducers and said comparing device in order to beactuated at its inputs by the checking and comparing pulses andproducing at one output the despatch of a checking symbol towards thestore position containing the printed character each time the two pulsesare present or producing at a second output the emission of an errorsignal when only a single pulse is active at its inputs.

4. Arrangement for checking printing according to claim 3, wherein ascanning circuit cooperates with said character store for detecting thata checking symbol has been entered in each position of the characterstore and for permitting the Writing of the characters of the followingline from the processing machine into said character store.

5. In a high speed printing machine in which all the characters of aline to be printed are stored in a character store and including arotating type drum, a plurality of striking devices and also acharacter-code generator operated in synchronism with said type drum, anarrangement for checking the effective printing of the charactersrepeatedly read-out from said store, comprising a transducer deviceemitting a checking pulse each time a striking device of a correspondingposition has been actuated, a delay device delaying the coded characteremitted by said code generator by a time duration at least equal to theresponse time of the striking mechanism, a code comparing device whichcompares the coded character emanating from said delay device with thecoded characters extracted from the store positions corresponding tothat of the struck characters in the printed line, and which emits acomparing pulse when the said characters are identical, a coincidencecircuit operatively connected to said transducers and to said comparingdevice to be actuated at its inputs by the checking and comparingpulses, and producing at one output the despatch of a checking symbolinto the store positions containing the printed characters when the twopulses are present, or producing at a second output the delivering of anerror signal when only a single pulse is active at its inputs.

6. Checking arrangement according to claim 5, wherein an analysercircuit is operativcly connected to said character store for verifyingthat a checking symbol is stored in each position of the character storeand for causing the entry or" the characters of the following line intosaid store.

7. In a high speed printing machine in which all the characters of aline to be printed are stored in a character store and including arotating typewheel, a plurality of striking devices and a character-codegenerator operated in synchronism with said typewheel, an arrangementfor checking the eifective printing of the characters repeatedlyread-out from said store, this arrangement comprising a series oftransducer devices each associated with a device for striking acharacter and for supplying a pulse when the striking device of thisposition is actuated, a register of which each registering stage isconnected to the output of a transducer for registering the pulseemitted by each transducer, a delay device delaying the coded characteremitted by the code generator by a time duration at least equal to theresponse time of the said transducer devices, a synchronising devicewhich produces the successive reading-out of the characters from thecharacter store, and in synchronism the sequential exploration of saidregister, a pulse comparator connected for constantly comparing thecharacters read-out from said store to said delayed character-code, acoincidence circuit receiving at one input a comparing pulse emitted bythe comparing device in the event of equality of the characters, and ata second input the reading pulse extracted from said register if a pulsehas been registered in the corresponding position, so that thesimultaneous application of a comparing pulse and of a reading pulse tothe said coincidence circuit produces at one output of the said circuitthe emission of a checking symbol, while the application of a comparingpulse in the absence of a reading pulse, or of a reading pulse in theabsence of a comparing pulse produces the emission of an error signal ata second output of the said circuit.

8. In a high speed printer including a continuously rotating typewheelhaving ty-pe elements arranged in rows parallel to the axis of saidtypewheel, and a row of striking hammers in proximity to said typewheel,the arrangement comprising a matrix memory for storing a number ofcharacter representations in memory locations, each containing at leasta further memory cell other than the necessary cells for all the codecomponents, first means cooperating with said memory for sequentiallyand repeatedly reading-out and re-entering all the characterrepresentations of the line to be printed, writing means adapted toenter a check symbol into said further memory cells, a number oftransducers emitting each a pulse each time an associated strikinghammer has effectively printed a character in a corresponding position,a register comprising a registering element for each printing position,said elements being connected to the corresponding transducers in orderto be set in a registering state upon receipt of said pulse so emitted,said register having an output terminal, second means for sequentiallyreading-out the content of said register, which content appears at saidoutput terminal, a generator for generating a difierent character-codeat each printing cycle, connected to feed a delay network and a registerfor a delayed character-code so that the latter is available after theemission of said pulses, a comparing device having inputs which areconnected to said first means and to said register for delayedcharacter-code, and having an output which delivers an equality signaleach time a character read-out from said memory is identical to saiddelayed character-code, and a controlling coincidence circuit havinginputs connected to the output of said comparing device and to theoutput of said register, and having also an output connected to saidwriting means for causing the latter to enter a check symbol each time acharacter has been efiectively and correctively printed.

9. Arrangement according to claim 8, comprising sequential locationselecting means which synchronously control both said first means andsaid second means.

10. Arrangement according to claim 8, wherein said first means arearranged to sequentially read-out also the contents of said furthercells of the memory, said arrangement comprising an analyser circuitconnected to the output circuit of said memory to verify after printingof a complete line that all of said further cells contained a checksymbol.

11. Arrangement according to claim 10, wherein said coincidence circuitfurther comprises an exclusive or device for emitting an error signal atits output.

References Cited in the file of this patent UNITED STATES PATENTS2,776,618 Hartley Jan. 8, 1957 2,799,222 Goldberg et a1 July 16, 19572,915,966 Jacoby Dec. 8, 1959 2,915,967 Gehring et a1 Dec. 8, 19592,941,188 Flechtner et al. June 14, 1960 2,966,113 Deerfield et al Dec.27, 1960 2,978,977 Eckert et a1 Apr. 11, 1961 Notice of Adverse Decisionin Interference I11 Interference No. 98,818 involving Patent No.3,064,561, A. Mauduit, DEVICE F OR CONTROLLING AN ELEOTRONIOALLYOPERATED PRINTING MACHINE, final judgment adverse to the patentee Wasrendered July 14, 1965, as to claims 1, 2 and 3.

[Oficz'al Gazette Septembew 28, 1,965.]

